arrythmia: therapy Flashcards
why does atrial fibrillation occur?
disorganised electrical signals
vaughan-williams classification class 1A
fast sodium channel blockade
vaughan-williams classification class 1B
intermediate sodium channel blockade
vaughan-williams classification class 1C
slow sodium channel blockade
vaughan-williams classification class II
B-adrenergic receptor antagonism
vaughan-williams classification class III
prolong refractoriness
vaughan-williams classification class IV
calcium channel blockade
what are Antidysrhythmics
cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart
what is the most common Antidysrhythmics
Digoxin
what does Digoxin do?
Inhibits the sodium-potassium ATPase pump
Positive inotrope—improves the strength of cardiac contraction
Allows more calcium to be available for contraction
Used for heart failure and atrial dysrhythmias (AF)
Monitor potassium levels, drug levels, and for toxicity
what are signs of digoxin toxicity?
nausea and vomitting xanthopsia bradycardia tachycardia arrrythmias
what is amiodarone used for?
used for VT and occasionally in supraventricular
whats the function of adenosine?
Slows conduction through the AV node
Used to convert paroxysmal supraventricular tachycardia to sinus rhythm
Only administered as fast IV push
May cause asystole for a few seconds
can antiarrhythmics cause arrhythmias
yes
indications for anticoagulations
atrial fibrilation: risk of stroke, peripheral emboli
what are characteristics of arterial thrombosis?
adherence of platelets to arterial walls
white in colour
associted with MI, stroke and ischaemia
what are characteristics of venous thrombosis?
Develops in areas of stagnated blood flow (e.g. deep vein thrombosis, left atrium),
Red in color-
Associated with Congestive Heart Failure, Cancer, Surgery.
indications for anticoagulation?
atrial fibrilation
DVT/PE
after surgery
immobilisation
whats the third commonest cause of death?
DVT/PE
how does increasing warfarin affect the affinity for albumin
decrease
how does increasing warfarin affect inhibition of degradation
increases
how does increasing warfarin affect synthesis of clotting factors
decreases
how does increasing drugs that promote bleeding effect platelets?
inhibits
how does increasing drugs that promote bleeding effect clotting factors
inhibits
how does decreasing warfarin activity effect metablosing enzymes?
induces them
ow does decreasing warfarin activity effect clotting factor synthesis?
promotes
ow does decreasing warfarin activity effect absorption
reduces it
what are drugs that promote bleeding?
aspirin, herparin, antimetabolites
what are drugs that increase warfarin activity?
aspirin, sulfonamides, cimetidine, disulfiram
direct effect of warfarin depends on…
concentration of warfarin in the liver
rate or accumulation of warfarin
what are adverse reactions?
bleeding
teratogenic
avoid in first and third trimesters
how do you monitor warfarin therapy?
Regular INR
Watch if therapy altered
Patient education
Alcohol intake
whaat is the acronym for assessing bleeding risk on warfarin?
CHADS2
congestive heart failure hypertension age >75 diabetes mellitus stroke
what are characteristics of the ideal anticoagulant?
oral no need for monitoring no interaction with food or drugs given once or twice a day as effective as warfarin safer than warfarin
